Proximity-based applications and services represent a fast growing social and technological trend that may have a major impact on evolution of cellular wireless/mobile broadband technologies. These services are based on the awareness of two devices or two users being close to each other and may include such applications as public safety operations, social networking, mobile commerce, advertisement, gaming, etc. Device to device (D2D) discovery is the first step to enable D2D service. With direct D2D communication, user equipment (UE) may communicate directly with each other without involvement of a base station or an enhanced node B (eNB). One issue with D2D communication is device discovery to enable D2D service. Device discovery involves discovering one or more other discoverable UEs within communication range for D2D communication. Device discovery also involves being discovered by one or more other discovering UEs within communication range for D2D communication. There are many unresolved issues with respect to device discovery for D2D communication including resource allocation and signaling, particularly for Proximity Service (ProSe) D2D discovery.
Reference will now be made to the exemplary embodiments illustrated and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope is thereby intended.